Edward bloomfield and dwight p



niwl graine geen eine.

EDWARD BLOOMFIELD AND DWIGHT P. o'ris, or NEW YORK, N. Y.

Letters Patent No. 90,150, dated Ma/y 18, 1869'. j

natPRovnMnNT IN PIANO-Pomme The Schedule referred to 1n these LettersPatent and making part o! the name.l

To all whom it may concern Beit known that we, EDWARD BLooMFrnLD andDWIGHT P. Oris, ofthe city, county, and State of New York, have inventeda new and useful Improvement in Piano-Fortes; and we do hereby declarethat the following is a full, clear, and exact description thereof,which will enable others skilled in the art to make and use the same,reference being had to the accompanying drawings, forming part of thisspecification, in which- Figure 1 represents a plan or top view of ourpianoforteimprovement.

Figure 2 is a detail transverse section of the same, taken on the linea: as, iig. 1.

Figure 3 is al vertical longitudinal section of the same, taken on theline ty y, fig. 1.

Sirhilar letters of reference indicate corresponding arts.

p The 'object of this invention is to strengthen the treble-section ofthe bridge in a. piano-forte, by apply. ing screw-pressure to a bar oflead or other heavymaterial, placed upon the bridge. j

These bridges are subjected to a considerable strain, and are apt tovibrate with the sound-boards, whereby the tone is very much injured.A

In a good instrument, the treble-bridge should be perfectly solid, andcan, nevertheless, not be made very high, as it should not project farabove the soundboard.

The bridges have therefore been frequently Weighted, but the Weightswere generally insuicient, unless made altogether too thick and clumsy..

We have avoided these inconveniences, by applying screw-pressure to abar placed upon the bridge, the screws working through a braceprojecting from and formed on the metal top-plate of the piano. The baris thereby firmly secured upon the bridge, and a clear sound will beproduced, as the bridge cannot vibrate the least.

A, in the drawing, represents the metal `top-plat`eof a piano.

B is the cast-iron 'brace of the same, nearest the treble-section of thepiano.

An arm, C, iscast on or fastenedto the plate A and. brace B, asshown,'so that it will be directly above the treble-section of thebridge D. E E are a series of screws fitted through the arm C,

F and bridge D. can be regulated to make the latter solid withoutstraining it.A

lWe are aware that screw-pressure has-heretofore been applied to thetreble-bridge of pianos, but this we do not claim broadly; but

What we da claim, and desire to secure by Letters l Patent, isy kThecombination of the heavy notched bar F, screws E, and arm C, with thebridge D, all arranged and operating substantially as herein shown anddescribed, for the purpose specified.

EDW. BLOOMFIELDL Dwrenr P. orrs. Witnesses FRANK BLOCKLEY, E. GREENECOLLINS.

'.lhe above specification of our invention signed by 'Y us, this 6th dayof January, 1869.

